Dynamics of dissolved organic carbon in hillslope discharge: modeling and challenges.
Dynamics of dissolved organic carbon in hillslope discharge: modeling and challenges.
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DOI：
10.1016/j.jhydrol.2016.12.054
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发表时间：
2017-03
影响因子：
6.4
通讯作者：
J. Dusek;T. Vogel;M. Dohnal;J. Barth;M. Šanda;A. Marx;J. Jankovec
中科院分区：
文献类型：
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作者：
J. Dusek;T. Vogel;M. Dohnal;J. Barth;M. Šanda;A. Marx;J. Jankovec
由于复杂的边界条件和土壤空间异质性，在山坡和流域尺度上对水的运动和溶解物质（特别是有机碳）的通量进行可靠的定量预测仍然是一个挑战。此外，微生物介导的溶解有机碳（DOC）转化被认为决定了土壤中DOC的平衡。到目前为止，只有少数研究在建模中利用了稳定水同位素信息，将溶解碳通量与混合和/或输送模型联系起来的研究就更少了。本研究采用基于物理的建模方法，分析了水分子中18o /16O比值（δ18O）和DOC的暴雨流动力学。采用一维双连续体垂直流输模式，模拟了森林坡地土壤2.5 A的地下输运过程。该模型用于描述δ18O和DOC输入信号转化为坡面暴雨流观测输出信号的过程。为了量化与模型参数化相关的不确定性，蒙特卡罗分析结合拉丁超立方体采样被应用。较好地预测了坡面流量和土壤孔隙水的δ18O变化。尽管微生物转化的复杂性导致了模式参数和DOC输运预测的不确定性，但模拟的暴雨流中DOC浓度的时间格局与观测到的DOC通量表现出相似的行为。由于优先流动的原因，坡地DOC出口的贡献比现有文献中通常发现的要高。
Reliable quantitative prediction of water movement and fluxes of dissolved substances – specifically organic carbon – at both the hillslope and the catchment scales remains a challenge due to complex boundary conditions and soil spatial heterogeneity. In addition, microbially mediated transformations of dissolved organic carbon (DOC) are recognized to determine the balance of DOC in soils. So far, only few studies utilized stable water isotope information in modeling and even fewer linked dissolved carbon fluxes to mixing and/or transport models. In this study, stormflow dynamics of18O/16O ratios in the water molecules (expressed as δ18O) and DOC were analyzed using a physically-based modeling approach. A one-dimensional dual-continuum vertical flow and transport model was used to simulate the subsurface transport processes in a forest hillslope soil over a period of 2.5 years. The model was applied to describe the transformation of input signals of δ18O and DOC into output signals observed in the hillslope stormflow. To quantify uncertainty associated with the model parameterization, Monte Carlo analysis in conjunction with Latin hypercube sampling was applied. δ18O variations in hillslope discharge and in soil pore water were predicted reasonably well. Despite the complex nature of microbial transformations that caused uncertainty in model parameters and subsequent prediction of DOC transport, the simulated temporal patterns of DOC concentration in stormflow showed similar behavior to that reflected in the observed DOC fluxes. Due to preferential flow, the contribution of the hillslope DOC export was higher than the amounts that are usually found in the available literature.